Hoping some fan favorites from series past would make it into Kingdom Hearts III? Well you should let it go. That notion, I mean. Let it go, like from the movie Frozone. Tangled was also confirmed at E3.
Anyways, Gematsu translated a Games Talk summary of Famitsu and Dengeki PlayStation interviews with Kingdom Hearts III director Tetsuya Nomura -- who Zack just interviewed at E3 -- cementing some key facts. There's an attack and magic system, versus any card deck thing, as well as "free running," things like wall running that give Sora more platforming ability.
Additionally, aside from Olympus, it seems most of the worlds will be new.
The game marks the end of Xehanort's story, but not the end of the series. A release window has been decided internally, but we won't likely know until a Kingdom Hearts fan event in November.